Poison ivy is expected to be one of the big winners of climate change, taking full advantage of warmer temperatures and rising levels of carbon dioxide in the atmosphere to grow faster, bigger, and more toxic. This could have implications for human health, as hikers, gardeners, landscapers, and others may want to take extra precautions to avoid an itchy, blistering rash.
Testing the theory
A team of researchers conducted an ambitious study in the late 1990s to figure out how plants and a whole forest ecosystem would respond to rising carbon dioxide levels in the atmosphere. They built large towers around six circular forest plots to pump the gas into the air and simulate what conditions would be like in 2050. Over a handful of years, the researchers watched the plants grow faster with more carbon dioxide. The vines grew even faster, and poison ivy was the speediest of all, growing 70% faster than it did without the extra carbon dioxide. The researchers also discovered that poison ivy became more toxic, producing a more potent form of urushiol, the oily substance that causes the nasty skin rash we all try to avoid.
A bigger itch?
With climate change already starting to affect global weather and atmospheric conditions and carbon dioxide levels in the atmosphere rising, experts think it's plausible that poison ivy is changing. Some conservationists in Massachusetts report they're seeing more of the vine growing around trails and yards. Doctors say they've seen more poison ivy rashes, including the kind that takes people to the emergency room. Roughly 80% of the population is allergic to poison ivy, but only a small fraction of cases make it to a doctor. The severity of the reaction all depends on how an individual's immune system responds to the oil in poison ivy.
Louis Kuchnir, a dermatologist with a practice of 10 doctors in the suburbs west of Boston, suspects there may be another culprit to consider in the uptick in poison ivy reactions in recent years - the pandemic shutting down indoor activities and nudging people into their gardens and onto trails. Just as more folks hit the trails, conservationists are noticing more poison ivy on paths and climbing up the trees. In Lincoln, Gwyn Loud has noticed that the leaves are getting bigger. Loud would like to see some hard data, but, if her observations are correct, it's not good news for the vast majority of people who are allergic to poison ivy.